Snap latch plug



0st. 5, 1954 s. w. PoLLocK 2,691,146

SNAP LATCH PLUG Filed MEICh l, 1951 BY 25a ATTORNEY I Patented Oct. 5,1954 SNAP LATCH PLUG Samuel Wilson Pollock, Camp Hill, Pa., assigner toAircraft-Marine Products, Inc., Harrisburg,

Application March 1, 1951, Serial No. 213,310

9 Claims.

This invention relates to electrical connectors of the type adapted forquick insertion and withdrawal, often referred to as hand plugs and moreparticularly in the illustrative forms set forth hereinafter to latchplugs wherein the latch is released only by a pull on the Wire.

In modern day electrical equipment, it is common practice to employconnector panels or boards wherein connector plugs are insertedselectively in corresponding receptacles to connect and disconnect thevarious control circuits. It is desirable that the plug be easilyremovable by a pull from the outside of the panel but not removable bythe push of the contact spring on the plug nose from the inside.

It is accordingly an object of this invention to provide a snap latchplug removable by a pull from the outer end. Another Aobject is toprovide a snap latch plug that will not be ejected by a push on the tipor by vibration. It is a further object to provide a snap latch plugthat will not become disassembled so as to drop short-circuiting partsbehind the panel. A still further object s to provide a plug that iseasily mass produced and substantially foolproof in operation. Otherobjects will in part be pointed out as the description proceeds and willin part become apparent therefrom.

I have discovered that the foregoing may be readily accomplished byproviding a resiliently actuated latch depressible by cam action duringinsertion and retractable by a pull on the end into which the conductingwire is inserted but engaging fully against other forces which wouldtend to eject the plug.

In this specication and the accompanying drawings I have shown anddescribed preferred embodiments of my invention and suggested variousmodifications thereof; but it is to be understood that these are notintended to be exhaustive nor limiting of the invention but, on thecontrary, are given for purposes of illustration in order that othersskilled in the art may fully understand the invention and the principlesthereof and the manner of applying it in various forms, each as may bebest suited to the conditions of a particular use.

The principles of the invention will be more readily perceived inconnection with the following detailed description of specificillustrative embodiments and from the accompanying drawings in which:

Figure 1 is a sectional view of a plug of the cam actuated latch typepartially inserted in the board;

Figure 2 is a sectional View of the plug of Figure 1 fully inserted;

Figure 3 is a plan View of the plug of Figure 2;

Figure 4 is a sectional view of another embodiment of a cam actuatedlatch type plug; and

Figure 5 is a section taken along line 5-5 of Figure 4.

Referring to Figures 1-3, a conducting wire 20 is crimped into a metalsleeve 22 which is part of a terminal connector 24 arranged to slidewithin the hollow plug shell 26. The terminal 24 presents a conical camsurface 2'! with a depression 28 at one end and a stop 3i! at the otherwhich engage a detent 32, one of the two fingers of the resilient latchsection 34 of the plug shell 26.

In operation the plug is inserted into a receptacle in the board 35 withthe latch section 34 in its normal flush relation (as shown in Figurel). After the plug is fully inserted, a push on the wire effects a camaction of the cam portion 27 against the latch detent 32 as the plungeris forced forward in the shell. This lifts the latch 313 so that itsstraight finger engages the board 35 to prevent withdrawal. When fullyinserted, the detent 32 drops into depression 28 to serve as a stopagainst accidental pull on the wire and against vibration, etc. Thelatch section 34 does not drop far enough to permit the plug to bepushed out by the force of contact spring 38, or to relax the springeffect of section 34, which thus maintains good Contact pressure betweenthe terminal 24 and the shell 25.

When it is desired to withdraw the plug, the conducting wire is pulled,which draws the terminal 2A to the rear until detent 32 abuts the head30 and allows the latch section to lie flush again. Further pull istransmitted by stop 30 to the shell 26 and the plug is thus withdrawn asa unit.

Thus this hand plug can be easily withdrawn by a pull from the outsideand yet cannot be pushed out from the inside.

In this embodiment while I obtain a simple positive action, it isnecessary to push the wire and sleeve into the plug to engage the latch.In Figure 4 is shown a self-latching plug that requires nothing morethan insertion of the plug to engage the latch.

The conducting wire 20a is crimped into a sleeve 22a of the terminal 2dawhich is adapted to slide within shell 26a. Latch spring Bda is formedso as to normally project through opening 38 with a cam part 32a and itsend adapted to abut against the board 35.

In inserting, the latch spring 34a, is depressed by its own cam section32a on contacting the panel board 35, until the .plug is inserted farenough to allow it to snap up on the inside and latch against the boardas shown in Figure 4. In removing ythe plug, a pull on the wire 20acauses section 40 (Figures 4 and 5) at the end of terminal 24a to camthe latch spring down until it is flush and Iallows the .plug to bewithdrawn. The latch spring 34a is made to contact the nose of the plugbefore the cam section 32a can contact the shell 26a so the springpressure on the nose cannot cam the section 32a of the spring back intothe shell so as to permit the plug to be ejected by a push on the tip.The latch spring 34a land terminal 24a are keyed to the shell byprojection 42 to `prevent accidental disassembly. -A slot 43 in theterminal accommodates the relative movement of the terminal in theshell. An insulating sleeve 44 is shown attached to the end of theshellbut is not essential to the present invention.

In this embodiment, I thus obtain a plug that requires no specialinsertion procedure, is easily mass produced, since all parts can bemade as stampings, and which meets the requirements of not being ejectedby vibration or -pressure yet being easy to withdraw by a pull on thewire.

Various modifications and additional applications will suggestthemselves to those skilled in the art. These embodiments shown are onlyby way of illustration and not limitation; all those modiiica'tionswithin the spirit of this invention being intended to be covered in theappended claims.

I' claim:

1. A Ahand plug of the ty-pe adapted to be connected to a wire andinserted into and withdrawn from a plugboard only by a pull on the wire,comprising, an integral outer shell open at one end and being closed andtapered at the other; an enlarged portion at said open end, an openingin said shell; a spring member having a latch portion positioned withinsaid shell with said latch portion .projecting through said opening inposition to be engaged with the rear face of said plugboard; a cammember positioned within said shell having at one end a cam bar engagingsaid spring latch and carrying yat the other end in said enlarged shellportion a ferrule forming portion whereby when a wire is engaged in saidferrule portion a pull on said Wire will `cam said latch into said shellto vpermit withdrawal of said plug from the plugboard.

2. A hand plug as described in claim 1 wherein said plug shell has asecond opening therein and said second opening carries thereon a detentyportion extending into said second hole to prevent accidentaldisassembly of said spring member, cam member and shell portion.

3. An electrical connector of the type adapted to be inserted into aplugboard comprising a shell, a terminal slidably mounted in said shelland adapted for connection to a wire inserted therein, a latch, means tolaterally project said latch through said shell for engagement with theplugboard when said connector is mounted therein, and means operativeupon relative axial movement of said terminal and said shell to withdrawsaid latch from engagement.

4. An electrical connector of the type adapted to be inserted into aplugboard yand held therein by a latching means releasable only by apull on a wire connected to said plug which comprises a unitary shellportion, a latch member adapted to laterally extend from said shell intoengagement with the rear face of said plugboard to secure said plugagainst removal from said plugboard by rearward pressure on the tipthereof, an actuating member positioned within said shell andoperatively engaging said latch member, a terminal portion axiallyslidably mounted within said shell and adapted for connection to a wireinserted therein, means joining said actuating member and said terminalportion whereby relative axial movement of said terminal and said shellby means of a pull on a wire connected to said terminal will retractsaid latch member and permit Iwithdrawal of said plug from theplugboard.

5. A device as described in claim 4 wherein said latch is an integralportion of said shell partially severed along longitudinal lines andsaid actuating member includes a cam whereby said latch is adapted to beextended radially by said cam to latch the plug into `a receptacle.

6. A device as described in claim 5 rwherein said integral latch.portion comprises a split tip, one part of said tip 4forming adepressed detent nger adapted to engage said actuating cam, and Ianotherpart forming a straight tip to engage the border of a receptacle tolatch the plug against Withdrawal.

7. A device as described in claim 6 wherein said actuating cam comprisesa cone shaped -portion on said terminal, having stops at each endadapted to engage the detent nger, a sleeve joining said cam to saidconducting wire within said plug.

8. A device as described in claim 4 wherein said latch comprises aspring having a cam section thereon adapted to project through saidopening in said shell to engage said plugboard, said actuating memberincluding a slide portion extending transversely of the axis of saidshell adjacent said cam section, said slide being movable toward saidsection yto cam down the projecting portion of said spring whereby torelease said plug from said plugboard.

9. A device as described in claim 8 wherein said latch and cam are keyedto the plug shell whereby accidental disassembly is prevented.

References Cited in the ile of this patent UNITED STATES PATENTS NumberName Date 2,336,385 Batcheller Dec. rI, 1943 2,405,400 Buttereld Aug. 6,1946 2,427,297 Modrey Sept. 9, 1947 2,496,732 rLyman Feb. 7, 19502,498,743 Theriault Feb. 28, 1950 2,521,516 Heidman Sept. 5, 19502,624,774 Cunningham Jan. 6, 1953 FOREIGN PATENTS Number Country Date480,469 Great Britain Feb. 23, 1938

